VS Code extension installs via a hand-built .vsix (from dev 83e472a96e36)

Folder copies into ~/.vscode/extensions no longer load in modern VS Code;
make_vsix.sh packages the extension (bash + python3 only) and the README
installs it with `code --install-extension`.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -41,7 +41,7 @@ are regenerated on each release — patches cannot be merged directly.
 Report problems (or send patches) to the author; accepted changes are
 applied to the development tree and appear in a following snapshot.
 
-This snapshot was assembled from development commit `eb5baf9cbe59`.
+This snapshot was assembled from development commit `83e472a96e36`.
 
 ## License